Pneumatic tool.



No. 866,370. PATENTED SEPT. 17, 1907. H. LEINEWEBER.

PNEUMATIG TOOL. APPLIUATION FILED FEB. 27. 1907.

UNITED STATES ,PATENT OFFICE.

HERMAN LEINEWEBER, OF SOUTH` CHICAGO, ILLINOIS, ASSIGNORVOF ONE-HALFA TO WILLIAM M. BAYNE, OF CHICAGO` ILLINOIS.

PNEUMATIC Toon Specification o'f Letters Patent.

Patented sept. 17, 190'?.

To altwhom it vmay concerm.

Beit known that I, HERMAN LnrNnwEnnn, a citizen' the work being performed by the tool, below the full' extent of vthestroke f vhich the tool is constructed. One form, and so far asI am now aware, the best form of means which I have devised for -the aforesaid purpose is illustrated in the accompanying drawing, in which- Figure 1 is a vertical longitudinal section of a pneu* matic tool providedl with my improvement; Figr 2, a' view showing 'in perspective a broken portion of' the trigger controlling the supply of airpressure to the tool for actuating the piston, with a stop adjustably supported upon it for regulating the extent of depression of the trigger to effect my pist()n-stroke-regulating purpose; Fig. 3, a view in elevation of the duct-containing bushing for the throttle-valve; Figs. 4, 5, 6, v7 and 8 are sections taken, respectively, at the lines 4, 5, 6, 7 and 8 on Fig. 3 and viewed in the direction of the arrow; Fig. 9 is a view of the bushing in longitudinal section, showing the throttle-valve in elevation within it in the position 'wherein it produces one-third of the full or normal piston-stroke; Fig. 10, a similar viewof the same showing the throttlewalve in the position wherein ton construction forming the subject of my application,-

it produces two-thirds of thenormal piston-stroke, and Fig. 11, a similar viewshowingthe position of the throttle-valve wherein it produces the full piston-stroke, Y

For illustrating my invention, I have selected the throttle-valve construction shown and described in Letters Patent of the United States No. 837,856, granted tome December 4, 1906, and the barrel and solid-pis- Serial Number 342,179, filed November 6, 1906; so' that reference to these may be had for a detailed disclosure of the tool herein illustrated in lesserdetail, ex-

cept as to the particular form of embodiment seleeted sages, preferably at uniform distances apart, one of which is indicated by dotted lines at 20 in Fig. 1. These passages lead from the forward chamber 14 rearwardly, and each terminates in a port indicated at 21. The barrel-wall also contains, to alternate with the passages 20, similar passages 22, one of which is indicated by dotted representation in Fig. 1, leading into the chamber 1li from a port indicated at 23. The piston shown is a solid body of.uniform diameter throughout between its ends, except for circumferential grooves 24 and 25 provided about it respectively near its opposite ends. The actuating pressure for the full-stroke operal tion of the piston is supplied, as hereinafter described,

entering the barrel at a port 26 through a passage 27, whence it enters a branch-passage 28 through a port 29, the passage 28 having a rear port 30 and a forward port 3 1.

With the piston in the position represented, namely at' the end of its forward stroke, pressure will pass through the port130 into the groove 25, whence it at-` tains the chamber 14 through the ports 21 and passages 2,0 and drives the piston backward, escaping through exhaust-ports, one'of which is shown at 32. In the retracted position of the piston lits groove 24 registers with the port 31 to admit pressure through the ports 23 and passages 22 into the rear chamber 16 for driving the vpiston forward, the pressure escaping through exhaust- Vports 33. This is all in accordance with the operation set forth in my aforesaid application.

A housing 34 is formed to extend diametrically across the wall of the rear end of the vbarrel formingfthe base of the handle 35, and terminates'at one end in a restricted extension 36 into which is'screwed the nipple 361 to connect the implement with the supply of airpressure by a flexible tube (not shown). A tubular bushing 37, coninedas a lining on the housing and open at the end nearest the port 26,' where it contains la port 261 registering therewith, is closed at its opposite end except for two grooves 38 and 39 formed longitudinally in its opposite sides to produce with the surrounding housing-wall air-ducts. communicating at one end with the nipple and terminating at their opposite ends in ports 40 leading to the interior of the bushing; and similar ports 41 lead from these ducts into the bushing beyond the center of the boss117 coincident with the opening 19 in which is an opening 19 in the bushing- Wall. A solid cylindrical throttle-valve 42, having a head 43 and recesses 45 and 451, is reciprocably confined and spring-pressed in the bushing to be actuated by a trigger 44 pivotally supported on the barrel to engage with the valve-head.

p By the valved construction last described, when the trigger is depressedlagainst the resistance of the valvei spring to register the valve-recess 43 with the ports 40,

ward movement of the throttle-valve, into registrationv with he port 191, air-pressure from that recess will enter the chamber 16 through the port -19 to act against the piston and drive it forward by overcoming the pressure at its impact-end in the chamber 14.

The described operation ofthe throttle-valve is the same as that set forth in my aforesaid Patent No.

On the trigger, Ain a hole provided immediately underneath its thumb-piece, is confined a spring-pressed rod 46, having a head 47 on one end and formed into a hook 48 at its opposite end. In the normal position of this rod its hook-end embraces the rear edge of the trigger just belowthe thumb-piece, asin Fig. 1, being held vthere by the retractive force of the spring. To release the rod for adjustment, it is pressed at the head 47 against the resistance of the spring to free the hook, and permit the rod to be turned on its axis to register the end of the hook with one of; a series (as two) of holes 49, 50, provided transversely through the web of the trigger; and upon release of the-iod, the spring will retract the end of the hook into the hole with which it then registers. In either of thetwo adjusted positions of the rod, its hook-end affords a' stop by extending across the plane of the handle 35 which it encounters 35'y in depressing the trigger, the hole49, when the stop is in it, permitting the trigger to be depressed farther andv the hole 50, when the stop is in it, permitting the, trigger to be depressed less far; and when the stop is in its rformal position, shown in Fig. 1, wherein it Will not encounter the handle, the trigger may be depressed to the full extent to produce the described full-stroke operation of the piston. Butv withdthe stop engaging either hole 49 or 50, the effect is to shorten the backstroke ofthe piston and cause the latter to be driven forward entirely'by the pressure introduced against it through the port 19, because of the following-described ensuing conditions: Y

Fig. 9 shows the throttle-valve in the position relativeto the ports 40 and 41 of` causing the piston to make only one-third of the extent of its full backstroke; Fig. 10 shows the same for producing only twothirds of such backstrokeL and Fig. 11 shows the rela- 'tiveposition of the throttlg-valve to cause the full baclrstroke of the piston. This division of the backstroke into thirds is arbitrary and is statedA by way of example, for the Iports may be arranged, without departure from the invention'fto vary the stroke to different proportions. As the parts are represented, when the stop 46 is adjusted into the hole 50, the resultantly permissible extent of inward movement of the throttlevalve opens on e-third of each port 40 to the ports 261, 26, permitting comparatively little pressure to pass through the passages 27, 28, port 30 and passages 20 into the chamber 14 to drive the piston back; and in making its backstroke it will, when the piston covers the exhaustports 33, encounter pressure in the chamber 16 introduced into iis-through. the ports 19, 191, from the valverecess 451 with whichhen, by the described inward movement of the throttle-valve,,two-thirds of each port 41 register, thereby perrnittingrelati'igoly greater pressure to enterthe chamber 16. Theair-pressure resistance in the chamberl 16 is suiiicientto'prevent greater extent of backstroke of the piston than will permitits goove 24 to register with the exhaust-ports 32 and exhaust the pressure from the chamber v14; but this extent of backstroke is insufficient to register' that pistonsgrooye with the port 31, soV thatdno pressure from the passage 28 can enter the chamber 16 to drive the piston forward, which therefore must depend for making its advance-stroke onthe, pressure introduced therein through the port 19. Moreoverit is found .in practice,that any pressure confined in the chamber 1 4 offers inappreciable resistance to the piston in making its forward stroke, because of leaking, under the force of the stroke, past the stem of the tool 13, which doesnot fit tightly in the barrel-end.

With the stop 46 adjusted into the hole 49 the-greater movement then permitted to the trigger before being arrested by the stop encounteringthe handle,' will bring the valve to the intermediate position represented iniFig. 10, wherein it uncovers'more, as two-thirds of the area, of each duct 40 to supply more pressure 'through the ports 261., 26, to the chamber 14 and ny crease the extent o f backstroke of the pistou, which is still resisted by the pressure introduced into the chain'- ber 16 through'the ports 191, 19, this pressure being supplied from the valve-recess; 451 with only onethird of thearea' of each port 41 .then open to it. v,In other particulars the operation is the same as that described with the throttle-valve in the vposition represented inFig. 9.'

The numberof adjustments and 4 form and arrangement of adjustable stop may be variously provided within my invention, Moreover, while I have selected A for convenience in explaining my invention, the particular barrel and piston construction-`illustrated and4 the means for overcoming the dead-point of the piston shown and described in my said patent No. 837,856, it is not the intention to be understood as limiting its employment l in those particular connections. The feature of the aforesaid dead-point overcoming meansr essential for use as part'` of my present invention, whether employed, or-not,.lfo`r"overcoming suchv deadr point, is a pressure-inlet port tothchamber 16 under controllable communication withthe pressure-supply by a throttle-valve; and the otheressential feature of my invention is suitable means for regulating the extent of movement of the throttle for the piston- Astroke-adjusting purpose herein describe/d.

What I claim as new and desire-toen -ure by Letters Patent is- 1. In :i pneumatic tool,.tlic conrlfiriarion with the .throttle-valve, of a trigger on the-'rl-handle engaging the valve for opening communication'with the air-pressure supply. :l plurality of holes 1 the trigger :it varying distances from the handle, und u stop .supported on the trigger and adjustable info engagement with any suid hole ro encounter the handle in depressing the trigger and arrest its vulve-opening movement, for Ille purpose set forth.

2. In a pneumatic tool, the combination of i bari-cl coutaining pressnre-chambers, a handle on the barrel, a piston cnnfim-d in )he bnl-rol to werk between said chambers, the rear ehnrnlilgrl having-m1 inlet-port communicating with the supply 0f nir-pressure for reciprocating the piston, s. thrutl'le-mlve controlling said communication, a trigger pirutnry supported on the handle t0 engage said valve for opi-niney coinmunlatlon with the airlpressure supply and provided with openings, :1nd a Spring-pressed rod rotatably supported on snid trigger :1nd longitudinally movable on its support and provided with a hook on one 10 end adapted to register with and engage said openingsAald extend into position to encounter the handle ln the inward/movement of the trigger, for the purpose set forth.

HERMAN LEINEWEBER.

In presence of R. A. SCHAEFER, J. II. LANDES. 

